1. Field of the Invention
The present invention relates to a vehicle lamp, and more particularly to increasing the positioning accuracy between a lens and a lens holding member, which are joined together through laser welding, by providing pluralities of welding portions and stopper portions on the lens holding member in such a manner as to project towards the lens.
2. Background Art
In some of vehicle lamps, a lens and a lens holding member, such as a lamp body which holds the lens, are joined together through laser welding. Specifically, a joining annular portion is provided on the lens holding member to which an outer circumferential portion of the lens is joined, so that the joining annular portion of the lens holding member and the whole (the full circumference) of the outer circumferential portion of the lens are joined together through laser welding.
When the outer circumferential portion of the lens and the joining annular portion are joined together along the full circumference through laser welding in the manner described above, the time taken for the welding work is extended in proportion to the laser welding joining being carried out along the full circumference of the outer circumferential portion of the lens and the joining annular portion and, due to the long working time, a variation in setting time depending upon portions on the outer circumferential portion of the lens and the joining annular portion occurs. This leads to the generation of strain between the lens and the annular joining portion. In addition, although high flatness is required for respective joining surfaces of the lens and the joining annular portion due to the outer circumferential portion of the lens and the joining annular portion being joined together along the full circumference thereof strain is generated in the lens and the joining annular portion depending upon the accuracy of the flatness. Thus, the positioning accuracy between the two components may become deteriorated.
There are vehicle lamps in which an outer circumferential portion of a lens and a joining annular portion are partially joined together through laser welding (for example, refer to Patent Document No. 1).    [Patent Document No. 1] JP-A-2005-339873
In the vehicle lamp described in Patent Document No. 1 above, because the laser welding is performed partially in such a state that the whole (the full circumference) of the outer circumferential portion of the lens and the whole (the full circumference) of the joining annular portion are in surface contact with each other, high flatness is required for respective joining surfaces of the lens and the lens holding member.
Consequently, it is not possible to eliminate the reduction in positioning accuracy between the lens and the joining annular portion due to the generation of stain based on the accuracy of the flatness.
Accordingly, a high accuracy control is required with respect to the lens and the lens holding member, causing the production costs of the vehicle lamp to be increased greatly.